Process for improving the physical properties of electrolytically deposited copper sheets



Patented June 23, 1925.

UNITED STATE-S'IPATENT OFFICE.

.' sumac SONODA, or KYOTO, JAPAN.

PROCESS FOR IMPROVING PHYSICAL PROPERTIES OF ELECTROLYTIOALLY DE- POSI'IED COPPER SHEETS.

No Drawing.

To all whom it ma concern:

Be it known that SHINco SoNoDA, a subject of the Empire of Japan, residing at N o. 458, Zaimoku-cho, Shimokyo-ku, Kyoto, Japan, has invented certain new and useful Improvements in Processes for Improving the Physical Properties of Electrolytically Deposited Copper Sheets; and he does hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a process for improving the physical properties of electrolytically deposited copper sheets whose utilization has been heretofore limited on account of its inferior qualities. This invention has for its object to increase the duetility and malleability as well as strength of said sheet and to make it more able to resist corrosive action by mechanical and heat treatment.

It is well known that ordinary electrolytically deposited sheet is smooth on one side and rough on the other, so thatit is sometimes called a one side polished sheet. An electrolytically deposited copper sheet is inferior to the ordinary polished sheet manufactured by the ordinary dry process on account of its poor tensile strength and many other properties, which restrict the scope of application of the electrolytically deposited sheet. Thus the ordinary electro lytically deposited sheet is only used for roofing purposes or the like where mechanical strength is not so required. In short, the ordinary electrolytically deposited sheet is brittle, nonductile or fragile, nonmalleable, corrosive and not uniform in its structure.

This invention comprises a series of mechanical and heat treatments of an electrolytically deposited sheet that is, annealing an electrolytically deposited sheet at a temperature of from 300 C. to 800 C. for a duration of 5 minutes or more, rolling the sheet at a circumferential speed of not more than 450 feet per minute, and pickling with dilute sulphuric acid. The three steps in the treatment are repeated until desired thickness of the sheet is obtained. In cold rolling, the plate easily cracks at its edges if Application filed June 12, 1923. Serial mi. $14,982.

each rolling step is not moderate. .Therefore care should be taken not to reduce its thickness too quickly in each rolling step.

The initial annealing step is however not so important that it cannot be conveniently omitted without serious disadvantage.

The copper sheet thus treated is very ductile and malleable, and is no more inferior in any properties to the copper sheet manufactured by the ordinary process in which the raw material is melted, cast, annealed and rolled. As an electrolytically deposited sheet is pure copper, the improved plate is especially. good for electrical purposes, for which high purity and considerable ductility are required.

Further, this improved sheet contains no blow holes and pin holes which are apt to form in sheets made by the ordinary dry process, so that sheetsv made according to the improved process are also, very desirable for mechanical purposes.

Furthermore, this improved sheet is homo geneous in its structure and resists corrosive action better than ordinary sheet.

Another characteristic of this invention lies in the fact that the cost of sheets manufactured by this process is lower than that of sheets made by other processes. This is true because, first, an electrolytic sheet is used and second, a thick electrolytic sheet is used. In the manufacture of electrolytic sheet, itis not necessary to melt, cast, and

then hot-roll in order to obtain a sheet of superior physical quality as is required in an ordinary process and, furthermore, a thick electrolytic sheet is cheaper than a thin electrolytic sheet per unit weight. In this connection, it is not necessary for the raw sheet to have a uniform thickness or smooth surface, so that ordinary commercial electrolytically deposited sheet of fair thickness and produced at low cost may be used as raw material.

Lastly, this improved plate has polished surfaces on both sides by the treatment of annealing, pickling and rolling. Therefore, this novel plate can replace the ordinary both sides polished sheet, which is far more expensive than the former on account of the necessary steps of melting, casting, hot rolling or any such mechanical and heat treatments.

-' What I claim is p 1. A process for improving the physical properties of an electrolytically deposited copper sheet comprising annealing the sheet at a temperature of from 300 C. to 800 C.

for a duration of minutes or more, rolling the same at a circumferential speed of not more than 50 feet per minute, and pickling the sheet with dilute sulphuric acid.

2. A process for improving the physical properties of an electrolytically deposited copper sheet comprising annealing the sheet 7 at a temperature of from 300C. to 800 C.

v for a duration of 5 minutes or more, rolling properties of an electrolytically de osited non-ferrous metal comprising annea ing a mass ofthe metal, rolling the same, and pickling.

4. The process of improving the physical properties of an electrolytically deposited properties of an electrolytically deposited non-ferrous metal comprising annealing a mass of the metal, rolling the same, and,

pickling, and then repeating all of the steps of the treatment until desired thickness of the sheet is obtained.

6. The process of improving the physical properties of an electrolytically deposited copper sheet comprising annealing the sheet, rolling the same, and pickling, and then repeating all of the steps of the treatment until desired thickness of the sheet is obtained.

7. The process of improving the physical properties of an electrolytically deposited copper sheet comprising rolling the same at a circumferential speed of not more than 450 feet per minute and then pickling.

In testimony whereof I hereunto afiix my signature in the presence of two witnesses. v

Witnesses W. OBIHARAH, 

